 .login-container {
     width: 100%;
     height: calc(100% - 20px);
     display: flex;
     align-items: center;
     justify-content: center;
 }
 .login-dialog {
     width: 400px;
     height: 320px;
     background-color: rgb(230,230,230);
     border-radius: 15px ;
 }
 .login-dialog h3 {
     text-align: center;
     padding: 50px 0;
     font-size: 20px;
 }
 .nav {

 }
 .login-dialog .row {
     height: 50px;
     display: flex;
     align-items: center;
     justify-content: center;

 }

 .login-dialog .row span {
     /*span是行内元素，直接设置width是无效的，需要将其设置成块级元素*/
     display: block;
     width: 100px;
     font-weight: 700;
 }

 #userName,#password {
     width: 200px;
     height: 40px;
     font-size: 20px;
     /*缩紧*/
     text-indent: 10px;
     border-radius: 10px;
     /*去掉边框轮廓线*/
     border: none;
     outline: none;
 }

 #submit {
     width: 300px;
     height: 40px;
     background-color: rgb(0, 128, 0);
     color: white;
     border: none;
     font-size: 20px;
     border-radius: 10px;

 }
 #submit:active {
     background-color: #666;
 }